Recovery of rhenium



May 3o, 1933.

F. H. DRIGGS RECOVERY oF RHENIUM Filed Oct. 3l, 1930 F5270( 770/1/-5#l/V319? 19597257 fa /000-96.

H2, 2.5, lys/95,2215.

{Ma/Mil INVENTOR FH F/GGS BY 277 a@ ATTORNEY Patented May 3o, 1933 W Y.

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PATENT- FRANK DRIGGS; 0F BLQOM'FIELD, NEWJERSY, AssIeNoR ToWEs'rINGHoUsE LAMP Ac'oivnaerr, a CORPORATION oF PENNSYLVANIA nncovnnx0F RHENIUM Application filed October 31, 1930. SerialNo. 492,397.

YThisinvention relates tothe art of metallurgy-andmore particularly tothe art of recovering metals lfrom ores and from raw materialscontaining. the metals in combination with associated'` impurities..More particularly this invention relates to therecovery of therare metalrhenium from its ores and crude concentrates.

One of the objectsof the present invention is to provide a method forseparating rhenium from its ores. i Y Y Another object of this inventionis to .provide a commercial process for the recovery of-rhenium fromores and crude concentrates thereof.

Other objects and advantages-will be apparent as the inventionvvisv-morefully disclosed. l f

v -Rhenium usuallyoccursinores, residues andthe like in extremelysmallamounts, usually not exceeding approximately 5%. `In such Vores andcrude concentrates. the

rhenium is .to be foundmost generally in combination vwith stronglybasic metal,

C Crude ores containing rhenium must,

therefore, be treated to'eifect thefremoval ,of carbon, sulphur,phosphorus and the like ,reducing agents and :to effect substantialdecomposition of the base metalrhenium lcompounds before the rhenium maybe separated therefrom as a'volatile rhenium'oxide compound (Re207). t

The yvolatilized rhenium oxide may then be recoveredA and treated -toeffect the-.re-

Vmoval ofv associatedimpurities and subjected to a reducing action to-convert'the hsame to metal.

In accordance with the objects ofthe pres-r 1 entv invention I havedevised a simple and efficient process whereby` rhenium may be recoveredfrom its crude ores and concentrates lby `directly volatilizing the samefrom'the ore as the higher oxide compound Which is recovered and reducedto metaL y This procf ess has been schematically outlined intheaccompanying drawing setting forth they flow sheet of the .process ofthe invention. The crude ores, residue or concentrates Ycontaining therhenium is rst roasted under oxidizing conditions to effect the removalof 'carbonaceous material, sulphur, phosphorus and other easily oxidizedmaterials; "Ihe rhenium by this step is converted ultimately into baselmetal rhennate .compounds inaccordance with thefollowing reaction:

The oxidized ore or crude concentrates is then charged into a retorttogether with a strongly acid compound, such as sulphuric acid,phosphoric acids, sodium bisulphate (NaHSOQ, commercial nitercakevoracid Yphosphate,compounds and heated to; temperatures approximating 300C., in the pres-` ence of an oxidizing agent, such as sodium nitrate. Af Y I preferably employ commercial nitercake or bisrulphate lcompoundsasthese maybe most expediently obtained on the market and more easilycommercially applied. The

amount'of the nitercake or bijsulphateem` ployed will depend primarilyupon/ the y nate compound to a volatile oxide compound A1n accordancetothe following reaction:

the fusion mixture of discreet amounts of` sodium nitrate (NaNOS). It'commercial nitercake is employed the addition of so@ dium nitrate to theretort will usually not be necessary.

At 300 C. rhenium oxide (Re207) is volatilized along with fumes of SOSand associated volatile acid impurities and may be collected in anysuitable manner, as by condensation 4in a suitable chamber or byabsorption in water, as has heretofore been `employed in the arts.

The sublimed oxides and the solution from the absorption tower may thenbe combined and collected inaqueous solution 1n suitable sizedprecipitation vessels or tubs from which the rhenium is. separated asthe sulphide by precipitation with ammonia and hydrogen sulphidefollowed by acidification with sulphuric acid in `a `manner heretoforedisclosed in the art. i

The precipitated sulphides `are then re covered from the solution in anyconvenient manner, as by iltering. It' arsenic is present in theoriginal ore the metal sulphides will be found to be contaminatedtherewith. The dried sulphide material may then be reduced to metal inany desired manner, as by heating to elevated temperatures in a hydrogenatmosphere.

It is preferable to employ the hydrogen reduction method on the sulphidematerial as arsenic and the like associated sulphide impurities areremoved as volatile products. Other `methods of reduction may beeinployed7 however, it desired, such as the calcium reduction method otU. S. Patent N o. 1,704,257 issued March 5,1929 to J. lV. @larden etal., or the electrolytic deposition method ot `copending applicationSerial No. 309,682, filed October l, 1928 by F. H. Driggs `et al., whichpatent and application is assigned to the same assignee as the presentinvention.

The rhenium metal powder thus prepared -is then converted to ycoherentform by agglomerating to any desired shape -or form and heat treating toelevated temperatures in vacua or in `a reducing atmosphere to effect acoalescence of the metal `powder par ticles to a coherent mass. Y i

Care should vbe taken that the metal powder be thoroughly degasiiedprior to the -final sintering thereof. It desired the metal powderproduct may be admixed with any' suitable organic binder and shaped ormolded as by commonly practiced extrusion methods to rod, filament andthe like articles for use in the arts. These articles may then besintered in any convenient manner to coherent bodies. i l

It will be apparent from the above disclosure that there may be manymodifications anddeparturesmade inthe specific embodiment disclosedlherein but such modifications and departures are anticipated as maytall within the scope ot' the following claims.

Vhat is claimed is:

1. The method ot treating `rhenium `bearing materialto recover the`:rhenium `content thereof which comprises subjecting thematerial to theaction of astronglyacid material which is substantially :non-Volatile attemperatures below approximately 1550o C. in the presence ot anoxidizing agent.

2. The method of `treating rhenium bearing material to recover therhenium content thereof which comprises subjecting thematerial to theaction of a strongly acid ma terial which is substantially non-volatileat temperatures below approximately 150 C. in the presence 'of anoxidizing agent capable of retaining the rhenium in the hexavalentstate. 1 i f w f i 3. The method 4of treating rhenium bearing materialswhich comprises admixingthe material with sodium acidsulphate and aproportion ot `an oxidizing agent and heating to temperaturesapproximately 300 C.

4. The `method of treating rhenium nbearing material which comprisesadmixing the material with sodium sulphate and a pro portion of sodiumnitrate and heating to temperatures approximately `300o C.

5. The method `of recovering rhenium from ores and'crude concentratescontaining the same which comprises heating `the rhenium containingmaterial under oxidizing conditions to elevated temperaturesapproximating 300O C. with a proportion fof a strongly acid fusionagent.

6. The method of recovering rhenium from ores and crude `concentratescontaining the same which comprises heating the rhenium containing`material admixed `with a proportion of commercial nitercake toelevatedtemperature approximating `300iJ '0.

`7. The method of i recovering rhenium from ores and crude concentrates`which comprises `heating'the` rhenium containing proximating 300o C.and collecting the volatilized rhenium oxide in any suitable manner. j

9. The method of recovering rhenium from ores and crude concentrateswhich comprises subjecting the rhenium containing material to a lowtel'nperature oxidizing step, admixingl the oxidized materia. With astrongly acid material Which is substantially non-volatile attemperatures bea 10W approximately 150 C. and heating the` admixture toelevated temperatures .a proximating 300 C. under oxidizing con 'tionsto effect a volatilization of the rhenium content as an oxide, andrecovering the Voxide in any suitable manner.

10. The method ofV recovering rhenium from ores and crude concentrateslwhich comprises subjecting the rhenium containing material to a lowtemperature oxidizing step, admixing the oxidized material With sodiumacid sulphate, and heating Vthe admixture to elevated temperaturesapproximating 300 C. under oxidizing conditions to effect avolatilization of the rhenium content as an oxide and recovering theoxide in any suitable manner.

11. The method of recovering rhenium from ores and crude concentrateswhich comprises subjecting the rhenium containing material to a loWtemperature oxidizing step, admixng the oxidized material with nitercakeand heating the admixture to elevated temperatures approximating 300 C.to eiiiect a volatilization of the rhenium content as an oxide, andrecovering the oxide in any suitable manner.

l2. The method of treating rhenium bearing material containingperrhenates which comprises, treating the material at an elevatedtemperature in the presence of anoxidizing agent and a strongly acidmaterial.

In testimony whereof, I have hereunto subscribed my namethis 29th day ofOctober, 1930.

FRANK DRIGGS.

